JPS6072335A - Identifying system of satellite beam - Google Patents

Abstract

PURPOSE:To identify the spot beam of a satellite irradiating a mobile station, by selectively catching nearest several bursts out of received control signal bursts so that the mean value of their received signal intensities becomes the maximum. CONSTITUTION:A received burst signal of a mobile station is demodulated into a base band signal by a demodulator 6 and introduced to a control burst detector 7 where a control signal burst is extracted. On the other hand, the received burst signal is also inputted into a level detector 8 and the received signal intensity of the received control signal burst is measured after the signal is correlated with the output signal of the detector 7. The received signal intensity information of the detector 8 is distributed to mean level detectors 10 and 10 and the mean received signal intensity is calculated. The calculated result is compared at a comparison deciding device 11 and the receiving timing nearest to a control burst having the larger mean received signal intensity is outputted. The spot bean in the control burst having the larger mean received signal intensity is extracted from the timing and the output signal of the detector 7 and outputted by a beam deciding device 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a satellite beam identification method in a satellite communication system using a communication satellite equipped with a plurality of spot beams.

(Background technology) In general, in satellite communication systems, there are severe restrictions on the power supply of the satellite, so how to use the power supply effectively is an important point in the economic design of the satellite. . In satellite communication systems for mobile objects such as maritime satellite communications, there are restrictions on the size of mobile station equipment, especially antennas, so in order to obtain the required line quality from the satellite to the mobile station, Satellite e, i, r, p
, (effective radiated power) needs to be made considerably larger, for example, about 100 times, as compared to that in a conventional inter-fixed station satellite communication system. In such a system,
The required satellite relay capacity, i.e. the required satellite e, i, r, p.
One of the ways to achieve this economically is to use multi-switch beams for the satellite's moving unidirectional transmitting antenna. When the direction of the mobile station is set to multi-spot vinyl, it is necessary to check both the fixed station side and the mobile station side to identify which satellite transmission spot beam irradiation area each mobile station is located in.

As for the method of beam identification, a method using a position measuring device mounted on a mobile station has been considered in the past. In other words, in the conventional method, a control channel between a fixed station and a mobile station using a global beam is prepared in addition to a communication channel using a spot beam, and the mobile station's communication device always uses a position measuring device to determine its own station position. Assume that data is being acquired. When the mobile station responds to a call from the fixed station or makes a call to the fixed station, the mobile station uses the aforementioned fixed station-mobile station control channel to notify the fixed station of its location, and the fixed station: Based on the position data notified by the mobile station, a spot beam that illuminates the mobile station is identified.

In addition, the mobile station identifies the spot beam irradiating itself based on the position data within itself, or the spot beam is notified from the fixed station via the above-mentioned fixed station-mobile station control channel. be done.

The conventional satellite beam identification method described above has the disadvantage that a control channel using a global beam must be used for beam identification, ie, call setup.

That is, it required a global beam satellite transponder to be mounted on the satellite, which was not necessarily required for the communication channel, making the satellite unnecessarily complex. However, in order to set up a control channel using a global beam satellite repeater using mobile station equipment designed to obtain the required line quality for the first time through a communication channel using a spot beam satellite repeater, the transmission speed of the control channel must be needs to be considerably lower than that of the communication channel, resulting in a lack of control information processing ability of the control channel.

Furthermore, the conventional satellite beam identification method requires the mobile station to be equipped with a position-measuring device, so it cannot be applied to mobile satellite communication systems for vehicles, etc. that are not equipped with such a device. There were drawbacks.

OBJECT OF THE INVENTION The present invention has been made to overcome the above-mentioned drawbacks, and its purpose is to provide the following: An object of the present invention is to provide a satellite beam identification method that makes it possible to identify a satellite spot beam that illuminates a mobile station.

(Structure and operation of the invention) FIG. 1 shows a first satellite communication system to which the present invention is applied.
FIG. 2 is a diagram conceptually showing an example. In the example shown in the figure, the satellite repeater 1 has a glow beam antenna 2 facing the fixed station.
In addition, the mobile station is connected to a plurality of spot beam antennas 4 via a time division switch 3, and the fixed station accesses the satellite using the TDMA method. A time division switch 3 on the satellite divides the received TDMA burst into
It is distributed to the destination spot beam antenna 4 in units of strikes.

In the present invention, first, the time division switch 3 is operated so that the repeater 1 connects to each spot beam antenna 4 at a fixed position in the frame of the TDMA line from the fixed station to the satellite. A specific fixed station (hereinafter referred to as a control station) uses the time slot to periodically send out a control signal burst containing a symbol indicating the spot beam antenna connected at that time. The mobile station always captures the control signal bursts that are received periodically at the above-mentioned period, and if multiple types of control signal bursts that are periodically received are captured at the same time, it receives the most recent bursts. By selecting and capturing the one with the highest average signal strength and extracting the symbol representing the spot beam antenna included in the captured control signal burst, the spot beam that illuminates the mobile station at the mobile station is determined. realization of identification. If the identification of the spot beam that illuminates the mobile station at the mobile station is completed at all times, by notifying the spot beam from the mobile station to the control station by appropriate means when setting up a call,
Location identification of the mobile station at the control station is realized.

FIG. 2 is an embodiment of the present invention, and shows a configuration example of a satellite beam identification device installed in a mobile station. The figure is
The figure shows the case where the number of spot beams is 2, 5 is an input terminal, 6 is a demodulator, 7 is a control burst detector, 8 is a level detector, 9 is a switch, 10 is an average level detector, 11
is a comparison judger, 12 is a beam judger, 13 is a timer, 1
4 is an output terminal. FIG. 3 is a diagram for explaining the implementation of FIG. 2, and is a diagram for explaining the implementation of FIG.
This figure shows an example of a frame structure of an MA line.

In the same figure, to simplify the explanation, time slots required for transmission burst synchronization between fixed stations when multiple fixed stations are operated and time slots for control information transmission of the time division switch 3 on the satellite are shown. (,) is the time slot for control signal burst transmission from the control station to the spot beam (A), and (b) is the time slot for control signal burst transmission from the control station to the spot beam (B). 1 (C) is the time slot for the communication channel from the fixed station to the mobile station. In the example in the figure, the time division switch 3 on the satellite
, ) to the spot beam (A) side during the time slot (b), and to the spot beam (B) side during the time slot (b).

In the embodiment shown in FIG. 2, the burst signal received by the antenna and receiver of the mobile station is first input to the input terminal 5, demodulated to a baseband signal by the demodulator 6, and then sent to the control burst detector 7. be led to. The control bar burst detector 7 detects the control signal burst,
That is, the bursts transmitted in time slots (a) and (b) are extracted.

The received burst signal input to the input terminal 5 is also input to the level detector 8, and the level detector 8 measures the received signal strength of the received control signal burst by comparing it with the output signal of the control burst detector 7. do. The received signal strength information of the control signal burst outputted from the level detector 8 is appropriately distributed by the switch 9 to the average level detectors 10 prepared in the same number as the number of spot beams. That is, the received signal strength information of the control signal burst transmitted from one spot beam antenna is input to only one average level detector 10. In each average detector 10, the average received signal over the number of TDMA frames of the control signal is calculated. The most recent reception timing of the control signal burst is output. Based on this reception timing and the output signal of the control burst detector 7, the beam determiner 12 extracts the spot symbol included in the control signal burst with the larger average received signal strength, and outputs it to the output terminal 14. will be output. Note that the reason why the average received signal strength is calculated over a plurality of TDMA frames is to take into account fluctuations in the received signal strength due to multi-A sphaging. Also, tie-13 connected to each output terminal of switch 9
, which divides the time length equal to the TDMA frame length, and receives the control signal burst sent from one spot beam antenna (outputs the S signal strength information to only one average level detector 10). like switch 9
Control the child.

FIG. 4 is another diagram for explaining the embodiment of FIG. 2, and shows a second frame configuration example of a TDMA circuit from a fixed station to a mobile station.

In the example shown in the figure, time slot (d) is a control signal for spot beam (4), NJ) beam ω.
), and the time division switch 3' on the time satellite is shared between the control signal bursts on the side of the spot beam (A) and the side of the spot beam (B).
The two sides are connected alternately for each ITDMA frame.

In the case of the example shown in FIG. 4, the timer 13 is set to 2 TDMA□7 frames 1 length, ゎ, □, □1-6. . , 1. It is possible to identify your own Dobby using the satellite bee identification device shown in Figure 2.

FIG. 5 is a diagram conceptually showing a second example of a satellite communication system to which the present invention is applied. In the example in the same figure, 5
A line from a fixed station to a mobile station is set up using the CPC//FDMA system. The signal from the fixed station received by the receiving station 2 is sent to the destination station, I? ) Within the frequency band exclusively assigned to each beam, JScpc4j is prepared and dedicated to each frequency band by filter 15. Middle school 115 minutes self-care 1, sending message 1? The signal is transmitted from the broadband antenna 4 to multiple mobile stations. In the satellite Renshin system shown in FIG. 5, a channel for control signal transmission is prepared for each spot beam 1, and the control station periodically sends control signal bursts using the control signal channel. , the present invention can be applied.

FIG. 6 shows a second embodiment of the present invention, which is a 4I applicable to the satellite communication system shown in FIG. 5 installed in a mobile station.
An example of the configuration of an r-star beam identification device is shown. The figure shows a case where the number of spot beams is two, 1G is a frequency converter, and 17 is a programmable local oscillator. 7th
The figure is a diagram for explaining the embodiment of FIG. 6, and shows an example of the configuration of a control signal channel from a control station to a mobile station. (a) is a diagram for explaining the embodiment of FIG. channel, and (b) shows the channel for the solar beam (B).As shown in Fig. 7, the control signal channel for each solar beam (B) is periodically controlled with an electrical period T. A signal burst is transmitted, and the burst transmission timings for both channels are staggered so that the bursts often overlap.The frequency of the received burst signal can be used to identify whether the signal was received or transmitted by a mobile station. Therefore, in the embodiments of FIGS. 6 and 7, there is no need to insert a symbol indicating a spot beam in the control signal burst.

In the embodiment shown in FIG. 6, the signal input to the receiver input terminal 5 is routed to a frequency converter 16 so that the received control signal burst is within the passband of the input filter in the demodulator 6. The frequency is appropriately converted so that it falls within the range. After the output side of the demodulator 6, the same signal processing as in the embodiment shown in FIG. 2 is performed, and satellite beam identification at the mobile station is realized.

The oscillation frequency of the programmable local oscillator 17 is controlled by the output of the timer 13, and at the reception timing of each control signal burst, the programmable local oscillator 17 converts the carrier frequency of the burst into the center frequency of the passband of the input filter in the demodulator 6. A signal of the required frequency is supplied to the frequency converter 16.

If the mobile station always identifies the spot beam that illuminates its own station using the method described above, the mobile station will receive the calling signal or response signal from the mobile station in addition to the call setup. By transmitting the emitted spot beam from the mobile station towards the fixed station using a suitable method having the function of displaying the spot beam, identification of the position of the mobile station at the fixed station is realized. Further, since the mobile station always identifies the spot beam that illuminates the mobile station, it is possible to send a calling signal or a response signal from the mobile station via a channel using a spot beam beam.

(Effects of the Invention) As described above, according to the present invention, first of all, in the control station, each time? I?, which is used for relaying to the irradiation area of 7 topimes. , the control signal burst having the function of displaying the L-beam antenna is sent periodically at a certain period, and the most recent few bursts from among the control signal bursts are periodically received at the next mobile station at the above-mentioned period. By selecting and capturing the one with the highest average value of the received signal strength, it is possible to acquire the same signal as the communication channel 1 and channel 2 without the help of other means. Satellite beam identification at the mobile station can be realized within the satellite beam repeater, eliminating the need for provision of a global beam repeater on the satellite for satellite beam identification and the need for provision of a positioning device at the mobile station. Furthermore, the effect of making it possible to improve the quality of the control channel can be obtained. In particular, it is possible to accommodate a mobile object such as an automobile that is not equipped with a position measuring device into a satellite communication system using a multi-spot beam repeater.

In the description of the above-described embodiment, the number of spot beam amplifiers is two for convenience of explanation, but this number does not limit the implementation of the present invention.

[Brief explanation of drawings]

FIG. 1 is a diagram conceptually showing a first example of a satellite communication system to which the present invention is applied, FIG. 2 is a block diagram showing the first embodiment of the present invention, and FIG. 3 is a diagram similar to that of FIG. A diagram showing an example of a signal configuration for explaining the operation of the embodiment.
A diagram showing another signal configuration example for explaining the operation of example i,
FIG. 5 is a diagram conceptually showing a second example of a satellite communication system to which the present invention is applied, FIG. 6 is a block diagram showing a second embodiment of the present invention, and FIG. FIG. 3 is a diagram showing an example of a signal configuration for explaining the operation of the embodiment. 1; Relay 4; Spot beam antenna for transmission Patent applicant: International Telecommunications 'Kamewa Co., Ltd. Patent application agent, patent attorney Megumi Yamamoto - Figure 2 Figure 3 Figure 4 Figure 5 Figure 5

Claims (1)

[Claims] In a satellite communication system using a satellite having a plurality of transmitting spot beams, the transmitting earth station transmits beams used for relaying beams toward the irradiation area of each transmitting spot beam antenna of the satellite. A control signal burst having the function of displaying the target beam antenna is periodically transmitted at a fixed period, and the receiving earth station receives multiple periods from among the control signal bursts periodically received at the above-mentioned period. □ Identify the transmitting spot beam antenna on the satellite that illuminates the receiving earth station according to the information displayed by the captured control signal burst. A satellite beam identification method characterized by: